Acoustic Wave Resonator Lid With Integrated Inductor for Compact RF Filters
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Solution Overview
Problem
Existing acoustic wave devices face challenges in integrating inductors without significantly increasing the device size, which is crucial for enhancing performance in radio frequency applications such as filters and phase shifters, while maintaining the integrity of passband frequencies.
Innovation Solution
The integration of inductors with the substrate or lid of acoustic wave devices, forming an inductor integrated substrate or lid, which includes spiral inductors on one or both sides of the substrate/lid, and utilizing overcoat layers with low dielectric loss materials to enhance performance without increasing the device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If inductors are integrated with the substrate or lid, then device size is reduced, but inductor performance and resonator coupling may be compromised
Solution Approach 1:
The inductor is integrated directly with the lid structure, merging two previously separate components (inductor and lid) into a single unified structure. This reduces the overall device volume while maintaining inductor functionality through careful design of the lid's conductive elements
Solution Approach 2:
The inductor design utilizes three-dimensional space by extending conductive elements through the lid thickness and employing spiral patterns that exploit vertical stacking. This dimensional approach allows compact inductor implementation without compromising performance
2Reliability
If inductors are integrated closer to resonators, then coupling coefficient is enhanced, but interference with passband frequencies increases
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the inductor and resonator. This mediator enables strong coupling through the dielectric while isolating the inductor's magnetic field from directly interfering with the resonator's passband frequencies, achieving both enhanced coupling and reduced interference
Solution Approach 2:
The coupling is optimized locally at specific regions where the inductor and resonator interact most effectively. The lid's conductive elements are strategically positioned and shaped to create localized strong coupling zones while maintaining overall frequency selectivity
3Productivity
If spiral inductors are formed on the lid, then bandwidth is increased, but device complexity increases
Solution Approach 1:
The inductor is formed as an integral part of the lid structure using the same conductive materials and manufacturing processes. This merging eliminates the need for separate inductor components and reduces assembly complexity while achieving enhanced bandwidth through the spiral configuration
Solution Approach 2:
The lid serves multiple functions: it provides structural support, acts as a shield, and incorporates the inductor functionality through its conductive elements. This multi-functionality reduces overall device complexity by eliminating separate components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This integration enhances the resonator coupling coefficient, improves return loss, and allows for miniaturization and increased bandwidth of acoustic wave devices, while mitigating interference and maintaining filter integrity.
Implementation Method 1
A bulk acoustic wave resonator can include a set of metal electrodes deposited on opposite surfaces of a piezoelectric material, generating a bulk acoustic wave within the volume of the piezoelectric material. The interaction between the electrodes and the piezoelectric material results in the formation and propagation of a bulk acoustic wave.
Implementation Method 2
an inductor formed with the lid, the inductor at least partially positioned over a portion of the resonator
Data Source
AI summary
An acoustic wave device is disclosed. The acoustic wave device can include a substrate, a lid, a resonator, and an inductor. The lid has a first side facing the substrate and a second side opposite the first side. The lid is coupled to the substrate. The resonator is positioned between the substrate and the lid. The inductor is formed with the lid. The inductor is at least partially positioned over a portion of the resonator.